• International Journal of Aeronautical and Space Sciences
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• v.15 no.3
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• pp.293-301
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• 2014

We present a study of vertical dynamics control of an electrostatically levitated gyro-accelerometer considering the wobbling effect and propose a tilt stabilization method with newly introduced control electrodes. Typically, a rotor in a vacuum rotates at high velocity, which may create a drift rate and lead to displacement instability due to the tilt angle of the rotor. To analyze this, first we set up a vertical dynamic equation and determined simulation results regarding displacement control. After deriving an equation for drift dynamics, we analyzed the drift rate of the rotor and the wobbling effect for displacement control quantitatively. Then, we designed new sub-electrodes for moment control that will decrease the drift amplitude of wobbling dynamics. Finally, a simulation study demonstrated that the vertical displacement control with the wobbling compensation electrodes mitigated the rotor's drift rate, showing the effectiveness of the newly proposed control electrodes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.3
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• pp.243-251
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• 2019

Recently, several studies were conducted on the micro-Doppler(MD) phenomenon to identify a warhead from decoys. Both, the warhead and decoy, can be modeled as various shapes and maneuver with their own micro-motion. Their MD phenomenon can be demonstrated by amplitude modulation and phase modulation. Most studies have utilized approximate solutions to express the amplitude modulation regardless of various warhead and decoy shapes. However, the exact solution of the amplitude modulation is required for more effective warhead identification. In this study, we proposed a new modeling method of receiving radar signals from warheads and decoys based on physical optics. The proposed solution was evaluated using an electromagnetic prediction technique and computer-aided design models.